AirLine实体类
package com.jason.bean;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
@Entity
public class AirLine implements Serializable{
private static final long serialVersionUID = -5617618540181055061L;
private AirLinePk id;
private String name;
public AirLine() {
super();
}
public AirLine(String startCity,String endCity, String name) {
this.id =new AirLinePk(startCity,endCity);
this.name = name;
}
@EmbeddedId
public AirLinePk getId() {
return id;
}
public void setId(AirLinePk id) {
this.id = id;
}
@Column(length=20)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
AirLinePk复合主键类
package com.jason.bean;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Embeddable;
/**
* 使用复合主键要满足的条件
*
* 1、要实现序列化 2、提供默认的构造方法 3、实现hashCode
*
* @author jason
*
*/
@Embeddable //embeddable: 可嵌入的
public class AirLinePk implements Serializable {
private static final long serialVersionUID = 7102936569989834678L;
private String startCity;// 出发城市
private String endCity;// 到达城市
public AirLinePk() {
super();
}
public AirLinePk(String startCity, String endCity) {
super();
this.startCity = startCity;
this.endCity = endCity;
}
@Column(length = 3)
public String getStartCity() {
return startCity;
}
public void setStartCity(String startCity) {
this.startCity = startCity;
}
@Column(length = 3)
public String getEndCity() {
return endCity;
}
public void setEndCity(String endCity) {
this.endCity = endCity;
}
@Override
public int hashCode() {
final int PRIME = 31;
int result = 1;
result = PRIME * result + ((endCity == null) ? 0 : endCity.hashCode());
result = PRIME * result
+ ((startCity == null) ? 0 : startCity.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final AirLinePk other = (AirLinePk) obj;
if (endCity == null) {
if (other.endCity != null)
return false;
} else if (!endCity.equals(other.endCity))
return false;
if (startCity == null) {
if (other.startCity != null)
return false;
} else if (!startCity.equals(other.startCity))
return false;
return true;
}
}
PKTest测试类
package junit.test;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import com.jason.bean.AirLine;
import com.jason.bean.AirLinePk;
public class PKTest {
private static EntityManagerFactory factory;
private static EntityManager em;
@BeforeClass
public static void setUpBeforeClass() throws Exception {
factory = Persistence.createEntityManagerFactory("jason");
em = factory.createEntityManager();
em.getTransaction().begin();
}
@Test
public void save() {
em.persist(new AirLine("PEK","SHA","北京飞上海"));
}
@Test
public void find() {
AirLine airLine=em.find(AirLine.class, new AirLinePk("PEK","SHA"));
System.out.println(airLine.getName());
}
@Test
public void update() {
AirLine airLine=em.getReference(AirLine.class, new AirLinePk("PEK","SHA"));
airLine.setName("北京飞上海啊哈哈");
em.merge(airLine);
}
@SuppressWarnings("unchecked")
@Test
public void list() {
List<AirLine> airLines=em.createQuery("select o from AirLine o").getResultList();
for(AirLine air:airLines){
System.out.println(air.getName());
}
}
@Test
public void detele() {
em.remove(em.getReference(AirLine.class, new AirLinePk("PEK","SHA")));
}
/**
* 用来判断映射是否成功
*
*/
@Test
public void test() {
Persistence.createEntityManagerFactory("jason");
}
@AfterClass
public static void tearDownAfterClass() throws Exception {
em.getTransaction().commit();
em.close();
factory.close();
}
}
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